The invention relates to a vehicle seat, in particular a utility motor vehicle seat, having a seat part, having a backrest comprising a lower backrest part and an upper backrest part, and having a holding device, by means of which the upper backrest part is mounted displaceably with respect to the lower backrest part.
The invention further relates to a utility motor vehicle, in particular an agricultural utility motor vehicle, comprising at least one vehicle seat.
A variety of conventional vehicle seats, in particular for utility motor vehicles and specifically for agricultural utility motor vehicles, are in various manners well-known from the state of the art.
In particular drivers of agricultural utility motor vehicles, during their work with these agricultural utility motor vehicles and the working equipment attached thereto, often take up a further, laterally or rearwardly orientated seated working posture—differing from the normal vehicle seat stance which is orientated forwards, in other words in the direction of travel—over a relatively long period, for example so as to be better able to reach and operate operating elements located at the side rear in the vehicle cabin, or else merely so as to be better able to observe working equipment which is attached behind the agricultural utility motor vehicle for a relatively long period.
So as to give the driver easier operating access to rearwardly located operating elements in this laterally or rearwardly orientated seated working posture, or merely so as to be better able to see or respectively observe a rear operating region behind a vehicle seat, Offenlegungsschrift DE 30 46 049 A1 discloses a vehicle seat in which the backrest is divided at least in two, and in this context accordingly has an upper backrest part and a lower backrest part, at least the upper backrest part being pivotable about a vertical axis. As a result, the driver can at any time turn his/her torso or respectively upper body, for example so as to reach the operating elements positioned behind the vehicle seat, since the upper backrest part can rotate about this vertical axis. In this context, the driver can indeed reach backwards past the lower backrest part without difficulty, since the upper backrest part is rotated about the vertical axis; however, with this solution the driver has very unsatisfactory support, or none at all, for his/her upper body in a corresponding laterally or rearwardly orientated seated working posture. The driver is thus not significantly supported by the upper backrest part.
In another, more recent solution, drivers can intermittently rotate the entire vehicle seat, in other words substantially the entire rigid seat construction including the seat part and the backrest, about a defined vertical axis of rotation by means of a rotation adapter, so as to be better able to reach a rear space within the vehicle cabin or respectively observe a rear space outside the vehicle cabin. In this context, the seat part remains stationary with respect to the backrest as a whole. Any accessories on the vehicle seat, for example a multifunctional armrest, thus rotate together with respect thereto. However, operating levers which are arranged further back to the side in the vehicle cabin still cannot be actuated comfortably as a result.
The latter solution further results in the driver having to turn himself/herself out of a comfortable seat cushion contour of the vehicle seat, so as in particular to be able to continue operating the pedals of the agricultural utility motor vehicle reasonably reliably. This in turn can lead to pressure points and thus to discomfort especially in the driver's buttocks and thigh region.
Specifically the back cushion contour is currently formed in such a way that the driver is supported as much as possible in the forwardly directed vehicle seat stance, without depriving him/her of the necessary degree of freedom which he/she requires for his/her movements in the driving operation. So as not to obstruct freedom of movement in the shoulder/arm region, the back cushion of the backrest must not be too contoured in the upper region. However, so as to ensure good support and thus sufficiently good load relief for the driver, a support surface should always be as large as possible in all driving positions. For the aforementioned reasons, such as the required degrees of freedom for good movement, this can currently only be achieved under some conditions and thus in an unsatisfactory manner, since the driver is alternating between two extremely different driving positions.
A further major drawback is that the possible pivot range of the rotary adapter is limited because, even when the rear operating equipment is being observed, the utility motor vehicle still has to be controlled safely via the pedals and the steering wheel. To meet these demands, the driver often has to take up a constrained posture, which inevitably leads to critical torsion of his/her whole body, over a relatively long period. Scientific studies additionally show that a constrained posture of this type can lead to damage to body structures in particular when vibrations are applied, especially if the body is not sufficiently well supported. It is further established that the load on the spinal column can be reduced significantly by good support via the backrest part.